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Title
Modelling of pulp properties during delignification on non-wood materials by DMF
Authors
Ahmad Ghozatloo and J. Mohammadi-Rovshandeh
Received
June 8, 2010
Published
Volume 45 Issue 5-6 May-June
Keywords
DMF, organosolv pulp, non-wood materials, viscosity, multiple linear regressions, MINITAB
Abstract
As an environmentally friendly solvent, dimethylformamide (DMF) creates mild pulping conditions and high selectivity during non-wood materials pulping. When using an aprotic DMF solvent, the main delignification reaction is hydrolysis. Pulping of non-wood materials by DMF was studied for stating the effects of the main cooking variables – such as cooking temperature, cooking time and DMF ratio – on the pulp properties, during DMF pulping. The responses of pulp properties to the process variables were analyzed with a MINITAB statistical software. The results obtained showed that acceptable pulp properties of non-woods could be achieved at 210 °C, 150 min and 50% DMF ratio, and also that the cooking temperature had a significant effect on pulping of DMF. The main factors involved in the analysis revealed that an optimum pulp from non-wood materials should have the following characteristics: 54.8% (yield), 82% (holocellulose), 66.3% (cellulose), 84.7% (?-cellulose), 41.4 (kappa number) and 1241 cm3/g (viscosity). Comparatively with the pulp properties of Kraft and DMF, it can be asserted that, basically, DMF plays a positive role, reducing cellulose degradation in the obtained pulp. Consequently, the protective action of DMF on non-wood materials against degradation under Kraft pulping conditions is considered as the main reason of the fairly high yield of DMF pulping and of the superior properties, compared to those of Kraft.
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